हिंदी
कर्नाटक बोर्ड पी.यू.सी.पीयूसी विज्ञान कक्षा ११

As the Wavelength is Increased from Violet to Red, the Luminosity - Physics

Advertisements
Advertisements

प्रश्न

As the wavelength is increased from violet to red, the luminosity ____________ .

विकल्प

  • continuously increases

  • continuously decreases

  • increases then decreases

  • decreases then increases

MCQ
रिक्त स्थान भरें
Advertisements

उत्तर

increases then decreases

 

The luminosity first increases up to 555 nm and then decreases.

shaalaa.com
Light Process and Photometry
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 22: Photometry - MCQ [पृष्ठ ४५४]

APPEARS IN

एचसी वर्मा Concepts of Physics Vol. 1 [English] Class 11 and 12
अध्याय 22 Photometry
MCQ | Q 3 | पृष्ठ ४५४

संबंधित प्रश्न

The luminous flux of a 1 W sodium vapour lamp is more than that of a 10 kW source of ultraviolet radiation. Comment.


The sun is less bright at morning and evening as compared to at noon although its distance from the observer is almost the same Why?


The one parameter that determines the brightness of a light source sensed by an eye is ____________ .


An electric bulb is hanging over a table at a height of 1 m above it. The illuminance on the table directly below the bulb is 40 lux. The illuminance at a point on the table 1 m away from the first point will be about ___________ .


Light from a point source falls on a screen. If the separation between the source and the screen is increased by 1%, the illuminance will decrease (nearly) by ____________ .


The intensity produced by a long cylindrical light source at a small distance r from the source is proportional to _________ .


A photographic plate placed a distance of 5 cm from a weak point source is exposed for 3 s. If the plate is kept at a distance of 10 cm from the source, the time needed for the same exposure is _____________ .


A point source of light moves in a straight line parallel to a plane table. Consider a small portion of the table directly below the line of movement of the source. The illuminance at this portion varies with its distance r from the source as ___________ .


A room is illuminated by an extended source. The illuminance at a particular portion of a wall can be increased by

(a) moving the source

(b) rotating the source

(c) bringing some mirrors in proper positions

(d) changing the colour of the source.


A source emits 45 joules of energy in 15 s. What is the radiant flux of the source?


A photographic plate records sufficiently intense lines when it is exposed for 12 s to a source of 10 W. How long should it be exposed to a 12 W source radiating the light of same colour to get equally intense lines?


Using figure, find the relative luminosity of wavelength (a) 480 nm, (b) 520 nm (c) 580 nm and (d) 600 nm.


The relative luminosity of wavelength 600 nm is 0.6. Find the radiant flux of 600 nm needed to produce the same brightness sensation as produced by 120 W of radiant flux at 555 nm.


A source emits light of wavelengths 555 nm and 600 nm. The radiant flux of the 555 nm part is 40 W and of the 600 nm part is 30 W. The relative luminosity at 600 nm is 0.6. Find (a) the total radiant flux, (b) the total luminous flux, (c) the luminous efficiency.


Light from a point source falls on a small area placed perpendicular to the incident light. If the area is rotated about the incident light by an angle of 60°, by what fraction will the illuminance change?


Figure shows a small diffused plane source S placed over a horizontal table-top at a distance of 2.4 m with its plane parallel to the table-top. The illuminance at the point Adirectly below the source is 25 lux. Find the illuminance at a point B of the table at a distance of 1.8 m from A.


Two light sources of intensities 8 cd and 12 cd are placed on the same side of a photometer screen at a distance of 40 cm from it. Where should a 80 cd source be placed to balance the illuminance?


Photo diodes are used to detect ______.


Light rays from a point object ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×